Schumed, what holds the racking arm into the valve? Is it threaded or o-ring/press fit?
I can answer that for you. The valve is a 3 piece assembly. There's the valve itself, which has a male threaded piece on the end. This has an O-ring on it, and it goes through the hole in the bucket.
For the inside of the bucket, there's a valve stem (the curved piece), a nut, and another O-ring.
You place another O-ring on the threaded valve piece on the inside, then insert the stem, and tighten it down with a nut.
I probably made that sound more complicated than necessary, but that's about it. The only criticism I might have is that they say to keep it finger tight, but if you rotate the setup counter-clockwise, you'll end up loosening the connection enough to likely spring a leak. This is easily overcome by simply rotating clockwise.